Chronometer-movement.



F. H. CORTHELL.

CHRONOMETER MOVEMENT.

APPmcAnoN man ^Pn.14,1915.

Patented Dee. 21, 1915.

UNITED sTAcTEs PATENT oEEroE.

FRED H. CORTHELL, 0F CHICAGO, ILLINOIS, ASSIGNOR T0 EDWARD R. HILLS, OF CHICAGO, ILLINOIS.

CHRONOMETER-MOVEMENT.

Application led April 14, 1915.

v T0 all whom t may concern:

Be it known that I, FRED H. ConTHELL, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Chronometer-Movements, of which the following is a specification.

This invention relates to improvements in clock and watch movements, and has for its principal object, as related to clock movements, to make feasible and practicable the employment of a balance wheel-controlled escapement in clocks employing weight or powerful spring motors such, for instance, as time recording clocks, in lieu of the pendulum-controlled escapement ordinarily used in such clocks.

As regards watch movements, the invention is designed to permit the employment of much lighter balance wheel escapements than would otherwise be necessary with a main spring of a given power.

The difficulty hitherto experienced in the effort to substitute a balance wheel escapement for a pendulum escapement in clock movements employing powerful springs or weights has been to so control the excess power transmitted from the motor through the gear train to the escapement mechanism that the latter will not overbank and fail to perform its proper function as a time measurer. As the ratios of the gears and pinions in standard clock and watch movements are constant, it has heretofore been necessary, when employing a balance wheel escapement, to carefully guard against the use of a motor that is too powerful for the escapement to control. Where pendulumcontrolled escapements are used it is, of course, not necessary to so carefully regulate the power of the motor to the retarding strength of the escapement; but in a great many instances it would be highly desirable, if practicable, to substitute a balance wheel escapement for a pendulum escapement in chronometers where a pendulum escapement is necessary to properly control excess power in the motor.

By means of my present invention I have solved this difiiculty, and have produced an improvement by the use of which a balance wheel escapement is entirely practicable in Specification of Letters Patent.

Patented Dec. 21, 1915.

serial No. 21,235.

clocks at present requiring pendulum escapements, and by the use of which the balance wheel escapement of watch movements may be made lighter than at present required with a main spring of a given power. The means by which the purposes of my present invention are effectuated and the mechanical embodiment of the invention itself are very simple, comprising, as the essential feature, a balanced power-absorbing weight that is applied to one of the arbors of the chronometer movement, preferably the escape wheel arbor, and, by exerting a retarding or dragging effect upon the intermittent movements of the gear train serves to control or hold in check excess power of the motor transmitted through the gear train of the movement to the escapement and thus prevent overbanking of the latter. In its simplest form this weight comprises a metal disk centrally mounted on the arbor or on the pinion carried by the latter, said disk being of suitable diameter and weight to effect the desired result in relation to the power of the motor. Where a very nice and exact regulation of the power-absorbing weight may be desired, the latter may be so constructed as to be variable or adjustable in its effect by making diametrically opposed portions thereof adjustable radially toward and from the center or axis.

The invention, its mode of operation, and the benefits and advantages attending the same will all be readily understood when considered in connection with the accompanying drawing in which I have illustrated practical embodiments and applications thereof, and in which- Figure 1 is a longitudinal section through a chronometer escapement mechanism, its support, and the fourth arbor of the gear train; Fig. 2 is a similar view of the lower portion of Fig. l, showing the power-absorbing weight, suitably proportioned, applied to the fourth arbor instead of to the escapement wheel arbor as in Fig. l; Fig. 3 is an elevation of a variable or adjustable power-absorbing weight which may be employed if desired in lieu of separate weights of varying effect in situations requiring different weights.

Referring to the drawings, 10 designates one of the plates of a. clock movement, and

l1 another plate secured thereto and to which the escapement is attached.

12 is the escapement bridge secured to the plate 11 by screws 13.

14; is the balance wheel bridge secured to the plate 11 by screws l5, and 16 is the pallet bridge secured to the plate 11 by screws 17.

18 designates what is ordinarily known as the fourth pinion stall or arbor ot the clock train, and 19 is the fourth pinion last on the arbor 18.

20 designates the fourth Wheel which meshes with and drives the escape pinion 21, this latter being tast on or integral with the escapement arbor 22. @n the forward end ot the escapement arbor 9.2 is the es- Lcapement wheel 23 that is controlled by the pallet 24 mounted on the pallet arbor 25. The pallet is ,connected in the usual manner with the balance stall 26 carrying the bal- Aance wheel 27.

The parts as thus tar described are or may be all as usual and well known in balance escapements of clocks and watches. ln

the instances shown, however, it may be noted that the escape, pallet and balance stalls or arbors are mounted in jeweled bearings, as is quite common in watch movenient-s; my present improvement making `feasible and practicable the application ot jeweled escapernents to cloclrs irrespective of the size ot the latter and the pov er ot the spring or weight motor employed.

'llurningnow to that feature wherein present improvement resides, 28 designates a weight, herein shown as taking the form oit a solid metal dislr, that is applied to the escape wheel .arbor 22, being1 herein shown as formed with a hub 28 fitted over an enlarged portion of the arbor forming a lateral extension of the escapement pinion 21 and secured thereto by a set-screw 29 eX- tending through the hub 2Q. i 'llhe weight 28 being1 in the form ot a solid metal dislr of uniform thickness and density centrally mounted on and with respect to the axis ot the escape wheel stall or arbor, absorbs apart ot the power ot the main spring or other motor to the extent or such power required to overcome the inertia of the weight at each intermittent impulse transmitted to the escape wheel arbor through the gear train. Said weicht, by thus absorbing the excess power transmitted to the escape wheel arbor, prevents the latter from imparting such a strong' impulse to the escape wheel as would overcome the regulating` efitect of the balance wheel and cause the escapeinent mechanism to overbanlr. rl`he momentum of the weight 28 is, or' course, at each impulse checked bv the (logging pawl of the pallet without injury to the parts, so that at each Yforward impulse imparted to the escape pinion 21 and its stad 22, the innient/oa ertia 01"' the Weight has to be overcome be- :tore any movement can occur; and the overcoming ot such inertia oit the weight absorbs the excess of the power which would otherwise be transmitted to the escape wheel, with the consequences above noted.

The power-absorbini` weight need not necessarily be applied to the escape wheel arbor, but may be applied elsewhere in the gear 'train as indicated in Fig. 2 where 28a indicates a weight in the torni oil a dislr mounted on and secured to the fourth pinion stall or arbor 18. lllhere the weight is thus applied it is necessarily ot considerably greater size in order to have the required power-absorbing' and regulating effect, so that the most practical place for the application of this power-absorbing weight is on the escape wheel arbor, as shown in llig. 1.

ln the practical use of the invention, the power-absorbing disk 28 may be made in a variety of sizes, so that a given chronometermoi/ement may be equipped with a weight giving' the right eilect by experimenting' with different sizes until the proper or correct weight for the movement is ascertained. la an alternative ot this, however, 'the weight may be made variable or adjustable as to its effect by so constructing it that diametrically opposed portions thereof may be adjusted radially toward and from the axis of the Weight so as to vary the inertia eilect ot the latter accordinp,` to the amount ot ei:- cess power required to be absorbed. ln Fig. 3 l have illustrated a single embodiment of such a variable power-absorbing member, wherein 30 designates a dislr adapted to be secured upon the escapement or other arbor of the movement in the manner already described, and 31 designates each of a pair of arms formed with weighted outer ends or bobs 32 and laterally extending inner portions 33 that are secured to the disk 30 by clamp screws Bt. These arms are connected for simultaneous inward and outward movement ot their outer ends by a link 35 pivoted at 3G to the end of one of the arms and at 37 to the elbow of the other. By loosening the clamp screws 34- and swinging,n the arms to the dotted line positions shown, the weighted ends or bobs 32 are simultaneously and equally adusted a sliohtly greater distance away from the axis, so that a correspondingly greater amount o't excess power in the motor is required to overcome the inertia. Obviously, many other methods oi eliectingr radial adjustment ot portions or" the weight might be employed.

The improvement represented by my present invention finds its chief utility Vin permitting: the use of balance escapements, jeweled if desired, on clock movementsenlploying comparatively powerful motors, where the use of an ordinary balance escapement would be utterly impracticable because incapable of withstanding and operating properly under the excessive power transmitted thereto from the motor.

I claim:

1. In a chronometer movement, the combination With one of the arbors of the movement, of a power-absorbing Weight applied to said arbor and serving to control excess power transmitted through the gear train of the movement to the escapement and prevent overbanking of the latter.

2. In a chronometer movement, the combination with the escape Wheel arbor, of a power-absorbing Weight applied t0 said arbor and serving to control excess power transmitted through the gear train of the movement to the escapement and prevent overbanking of the latter.

3. In a chronometer movement, the combination with one of the arbors of the movement, of a balanced power-absorbing weight applied to said arbor and serving to control excess power transmitted through the gear train of the movement to the escapement and prevent overbanking of the latter, said Weight having diametrically opposed portions thereof adjustable radially toward and from the axis of said arbor.

FRED H. CORTHELL.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

